Several prior art references have already taught hair styling compositions including one or more carrageenans as an ingredient.
For instance, U.S. Pat. No. 6,132,704 discloses a hair styling gel composition comprising (a) a carboxylated polyurethane, (b) a viscosity enhancer, (c) a carrier comprising water, and (d) optionally up to 6% by weight of a second hair fixative resin which can be sodium carrageenan. This aqueous formulation can also contain up to 2% by weight of a conventional hair care adjuvant such as glycerine. No hint is given as to the specific type of carrageenan optionally used.
U.S. Patent Application Publication No. 2008/279,804 discloses a hair styling composition which binds to the hair surface due to charge and ion interaction and which comprises (a) 0.05 to 5% by weight of sodium magnesium silicate, (b) 0.05 to 1.5% by weight of a preservative, (c) optionally a thickener which can be a carrageenan in an amount of up to 5% by weight of the composition, and (d) water forming the balance. No hint is given as to the specific type of carrageenan optionally used. When the hair styling composition is a shampoo or a spray, it may further comprise up to 15% by weight of a humectant such as glycerin.
U.S. Patent Application Publication No. 2005/137272 discloses aqueous dispersions comprising:                (a) a gel forming polymer which may be a carrageenan,        (b) a gelling agent comprising a divalent, preferably calcium, cation capable of forming a gel at a pH of 3 or higher,        (c) a water soluble plasticizer such as glycerin,        (d) a pH modifier, e.g. a lactone, typically lowering the pH of the aqueous dispersion during gel formation, and        (e) water,wherein the plasticizer comprises more than 50% by weight of the dry gel.        
U.S. Pat. No. 6,623,727 discloses a solid gel composition for hair treatment comprising, in an aqueous or aqueous-alcoholic base (wherein the alcohol, e.g. glycerol, may be present at a content up to 40%), a combination of (a) 0.5 to 5% by weight of a carrageenan or mixture of carrageenans optionally admixed with a sugar such as dextrose and (b) at least one additive selected from the group consisting of hair fixing polymers, amphiphilic associative thickeners, salts containing calcium or potassium ions, mono-alcohols and polyalcohols. Kappa-carrageenan and iota-carrageenan are both suitable as component (a) of this gel composition. If the gel-former or the additive are not completely soluble at room temperature, heat can be used to dissolve them e.g. at about 40-80° C., then the resulting solution is allowed to stand until it solidifies to form the gel.
WO 2006/042588 discloses a hair styling product containing a foamable or sprayable, gel-type emulsion, in combination with a device for spraying or foaming the emulsion, said emulsion comprising (a) at least an ester of a polyalkoxylated polydimethylsiloxane, (b) at least an emulsifier, (c) water, and (d) at least a thickener which can be a carrageenan, in particular kappa-carrageenan and/or iota carrageenan, in an amount from 0.1 to 10% by weight.
U.S. Pat. No. 6,719,967 and U.S. Pat. No. 6,673,371 both disclose a hair treatment composition having a thickened fluid form and comprising:                (i) a first phase comprising a naturally derived polymer capable of forming a reversible gel, e.g. a carrageenan, and being present as a shear gel having multiple separate gel particles formed by subjecting the polymer to shear while gel formation occurs, and        (ii) a second phase suspended therein, being selected from the group of conditioning agents, solid active agents (e.g. antimicrobials, dyes or colorants), opacifying agents and pearlescing agents.This composition displays a viscosity in the range of 0.1 Pa·s to 1000 Pa·s at a shear rate of 10 sec−1 measured at 20° C. This composition may further comprise preservatives, or glycerine, at a level of up to 5% by weight. When the composition is formulated as a hair styling gel, it further comprises a water-soluble film-forming resin being a synthetic polymer. U.S. Pat. No. 6,719,967 and U.S. Pat. No. 6,673,371 also teach that:        other types of carrageenan may be used in mixtures with kappa carrageenan, and        aqueous solutions of iota carrageenan exist as reversible gels, but appear to be self-healing; therefore iota carrageenan can be used, but the resulting compositions become lumpy during storage because of the self-healing property of iota carrageenan gels.        
The hair styling compositions of the prior art which include one or more carrageenans as an ingredient usually also include one or more synthetic polymers for performing functions such as, but not limited to, hair fixation. They can therefore be qualified as synthetic gels.
For obvious environmental reasons, one problem addressed by the present invention is the design of an entirely natural hair styling gel composition, i.e. a hair styling gel which is free from synthetic polymers but still performs the hair styling function, in particular the hair stiffening effect, in the same way as a synthetic gel.
Another problem addressed by the present invention is the development of a specific mixture of seaweed extracts which can be used as a cosmetic ingredient and which can avoid the need for synthetic polymers in making efficient cosmetic formulations such as, but not limited to, hair styling products.
The basic structure of carrageenans is a linear polysaccharide made up of a repeating dissacharide sequence of β-D-galactopyranose linked through positions 1,3 (A residues) and α-D-galactopyranose residues linked through positions 1,4 (B residues). The regular backbone structure of the basic structure of carrageenans is disrupted by a more or less ordered distribution of sulphate groups. Some of the galactose units have attached sulfate groups, while others are unsulfated. The three main types (iota, kappa and lambda) of carrageenan molecules differ by (1) the types of linkages between the galactose units, and (2) the point of attachment of the sulfate groups to the galactose units. These apparently small differences in chemical constitution and structure make major differences in the properties of each type of molecule.
Gelling in carrageenan is caused by helix formation and this can only occur in repeat structures where the B residue is in a 1-C-4 conformation. Lambda carrageenan (theoretically having 3 sulphate groups per repeating unit) has both its sugar residues in a 4-C-1 conformation and therefore does not form gels. It is therefore known to the skilled person that lambda carrageenan should be avoided when gelling is a strong requirement of the end use of a formulation including carrageenans.
All the gelling types of carrageenan which include the kappa type (theoretically having 1 sulphate group per repeating unit; the most naturally abundant type of carrageenan molecule) and the iota type (theoretically having 2 sulphate groups per repeating unit; the least naturally abundant type of carrageenan molecule) all contain a 3,6-anhydro bridge on the B unit which forces the sugar to flip from a 4-C-1 conformation to a 1-C-4 conformation and can then form cross-link networks and gels. However, kappa carrageenans may be prevented from gelling by the addition of sodium salts to the gum solution.
Some types of seaweed species contains relatively pure carrageenan fractions. Kappaphycus Alvarezii contains largely κ carrageenan and μ carrageenan which may be converted to kappa carrageenan by alkali treatment. Eucheuma Denticulatum contains a similarly high level of ι carrageenan with some v carrageenan precursor. Other seaweeds are more mixed in their carrageenan content. Furcellaran contains a strong gelling type carrageenan which is a mix of kappa carrageenan and β carrageenan in a roughly 3:2 ratio. Other seaweed types, such as Chondrus crispus and Gigartina types contain not only a mix of κ and λ type carrageenans but also a type of carrageenan polymer that is essentially a block copolymer of different carrageenan types. This gives the carrageenan made from Gigartina or Chondrus weed species quite different properties from those made from the Eucheuma type species from South east Asia.